Reduce your personal risk (created by Michael Paine, May 2008)
Be alert and
prepared - not alarmed. This is a
low-probability, high-consequence event that calls for a little
preparation in case a warning is issued.
These are similar to the things that people do to
prepare for cyclone warnings in tropic areas and bushfires. The following advice applies mainly where there is no local tsunami action plan.
Although the likelihood of a mega-tsunami is low there are some simple
things you can do to significantly reduce the risk of fatality:
- Identify if you live, work or play in a vulnerable
location -
find out the approximate height above mean sea level. As a rough
guide coastal and estuary
land less than 10 metres above mean sea level is "at risk" and 5m or
less should be considered "vulnerable". Google Maps has a sea
level rise add-on
(update: no longer available - try this tips page or Sea Level Rise Explorer) that can give a very rough guide (detailed
modelling is needed to assess vulnerability as there are many
factors that influence tsunami inundation). The following
links are to JPG screen
snapshots from Google Maps in 2008 - red shows 5m contour and yellow shows 10m
contour: - Narrabeen,
Manly,
Sydney
, Brisbane,
Gold
Coast, Sunshine
Coast, Nowra,
Wollongong,
Gosford,
Newcastle
and Forster
(Update Dec09: There are more accurate maps being developed by SES
organisations and this page will link to them when they are published
on the internet or try Sea Level Rise Explorer). Update June 2016: NSW SES now has similar maps online. See the Central Coast (Gosford) maps here: 5 Nov 2017: Tsunami safety day at Ettalong Beach.
- Identify a safe location to go to in the event of
a tsunami
warning - a nearby hill or headland or at least the third
storey of a
reinforced concrete building
- Plan an evacuation route by foot to reach that
safe location (avoid the need for driving a car because the roads will
likely gridlock)
- Subscribe to the email or RSS warning service
of the US
Pacific Tsunami Warning Center
- Subscribe to a mobile phone alert
service like the Australian Early Warning Network
which offers anSMS service that relays tsunami warnings issued
by the Australian Bureau of Meteorology.
The service also
covers other risks such as bushfires and cyclones. SMS-Tsunami-warning.com is a similar international service. With hundreds of
thousands of people potentially afffected, you may not be able to rely
on the Internet, landline telephones or mobile phones at the height of
a tsunami emergency so have a portable radio available for receiving
updates.
- If you receive a tsunami
warning that is relevant to your location, or feel an earthquake, quickly
get your evacuation plan into action. If a mega-tsunami does
inundate the area do not return to low-lying land until given the all-clear by emergency services as other waves are likely to
follow after the first wave and each wave can last for 20 to
30 minutes. The danger may last for many hours and possibly more than 24 hours.
- Approach your local council and politicians and
ask to support (ie fund) State SES to develop tsunami
warning action plans and infrastructure (such as a public address
system) and to have inundation modelling carried out. See
the [NSW] State
Tsunami Plan(
pdf 2311kb) - issued in 2005. See Tsunami Notification Zones for British Columbia as an example.
- Most importantly, relax and enjoy living
near the ocean, knowing that you have made basic
preparations for a worst case scenario
Update Nov09: Brochure "
Tsunami Survival Guide" based on the above tips
"If you are at the beach and feel an earthquake – GO TO HIGH GROUND" -
don't wait for a tsunami warning signal because the tsunami could arrive in less than 30 minutes (advice from Tsunami expert
Dr Charles Mader, who sadly died on 18 August 2018)
Tips from a tsunami survivor
These tips are from Kristin Fedorow, an Australian who survived the 2004 tsunami on the Thai coast:
1) Tsunamis usually have more than one wave
2) The later waves are usually much bigger
3) The water does not necessarily recede before the wave approaches
4) The wave does not necessarily look big as it comes in
5) The time between waves can be much longer than a few minutes
These points are illustrated in this Youtube video:
Japanese mega-tsunami in 2011
and this confronting movie about the 2004 tsunami:
The Impossible.
The Norwegian move
The Wave (2015) has a strong message about community preparednes
Slide show presentation on the tsunami
hazard to Sydney (by Michael Paine at a Friends of Narrabeen Lagoon
Catchment meeting, March 2008)
Includes recent computer modelling of a mega-tsunami from the Tongan
Trench that has similar features to the 2004 Indian Ocean
Tsunami.
- 12Mb
Quicktime presentation + Youtube version
- 3Mb
PDF of the presentation
- Notes
for simulation of an Magnitude 9 earthquake at the Tonga Trench
by Dr Charles Mader (from the DVD with his text book Numerical Modeling of
Water Waves).
The chances of such an extraordinary but deadly event are unknown at
this stage (however, a magnitude
7.9 earthquake occurred near Tonga in 2006 and a Magnitude
earthquake 8.1 occurred south of New Zealand 3 days before
the 2004 Indian Ocean event. Update: 8.3 quake near Tonga on 30 Sep 09). The Mader modelling was based on the
actual tectonic movements
for the Sumartran earthquake that caused the 2004 Indian Ocean tsunami
(Aug08: assumption
independently confirmed).
Others have noted that the Tongan Trench is the fastest known
subduction zone. The resulting tsunami is particularly devastating for
the East Coast of Australia, with a predicted height of
around 10m
(the deep water wave height would be less than that modelled
due
to dispersion but the shallow water amplification would counteract this
effect meaning a likely 10m runup along many coastlines). Apr 11 New Scientist: Japan disaster suggests that Tonga is not immune to a Magintude 9 earthquake.
- It has been estimated
that 330,000 people
live within the 10m elevation zone along the coast (and many estuaries)
of New South
Wales. Adding the Queensland
Coast the population at risk is likely
around half a million - something that deserves
urgent attention.
- Recent Geosciences Australia modelling
indicates that a Magnitude 8.5 earthquake in the Tonga region is
unlikely to pose a major mega-tsunami threat to the Australian coast -
which is good news. The Magnitude 9 quake modelled by Dr Mader much
larger and much less likely to happen in our lifetimes. More about the risk to Australia.
- 19 Aug 14 Scientific American: Big Earthquake Looms for Chile - a long way from Australia but a potential tsunami threat. This Wikipedia page has info about the 8.2 magnitude 2014 Iquique earthquake that generated a 2.1m local (Chile) tsunami.
Travel time to the Australian East Coast was 17 hours but the tsunami
height was negligible. However an 8.5 magnitude earthquake near Peru in 1960
generated a small tsunami in Sydney and the largest tsunami in Hawaiian
history - see the lecture by Charles Mader SWModel1.mp4 (download from here) at around 24 minutes into the talk. Also New Scientist: Chile is facing yet another massive earthquake "Fortunately Chile has good systems for responding to earthquakes... It
holds major evacuation drills involving thousands of people. In coastal
regions, evacuation sirens warn of impending tsunamis, and alerts are
sent to cellphones and through Twitter." + Why the [2010] Chile quake tsunami was smaller than feared
- 28 Aug 14 Uni Queensland: South east Australia most prone to tsunami threats along eastern coast.
- Reducing
The Death Toll From Tsunami (written a fortnight after the
Indian Ocean disaster)
- 15 Aug 08 Breakthrough! Illawara Mercury:
Tsunami a real threat to Illawarra: professor - a
tsunami education and evacuation plan for Illawarra would be released
in November.
- 19 Apr 09 - Tasmanians becoming prepared.
- 1 Oct 09 ABC: 'No agreement' on [Australian] tsunami alert system - Emergency services experts say Australia's tsunami warning procedure is still lacking an effective alert system [following the Samoan tsunami].
- 1 Sep 14 Cahill Expressway interpretive display:
The Great Eel at Boora Birra [an aboriginal account of the creation of
some of Sydney Harbour, according to F. Bodkin, 2001]: ...The Earth
began to shake violently, and a great chasm opened up
in the ground, following the fleeing lawless ones and swallowing them
as they fled towards the flatlands. Then a storm came in from the sea,
and the waves crashed across the flatlands until they reached the cliffs that marked the beginning of the highlands. [this could well be a description of mega-tsunami, such as the one that probably arose from the Bulli Slide a few hundred years ago]
- 25 May 2015 New Scientist: New Zealand's worst earthquake fear confirmed by sediment survey - evidence of a huge megathrust earthquake crossing segment boundaries there some 500 years ago [source of the mega-tsunami on the east coast of Australia?] BSSA Abstract.
Update 2008
- Geoscience
Australia tsunami page with a brochure
link. Opinion: the tsunami hazard to the east coast appears
to be under-rated.
- Echoes
of ancient tsunamis
(2006) Along the eastern Australian coastline, where most
Australians live, the tsunami threat comes from several sources.
Although they have produced few historical tsunamis, the Solomons
trench, the New Hebrides trench off Vanuatu, the
Tonga–Kermadec
trench north of New Zealand, the Alpine fault in New Zealand and the
Puysegur trench south of New Zealand may all have the potential to
produce earthquake-generated tsunamis capable of reaching Australian
shores. More work needs to be done to characterise the
earthquake mechanisms in these regions... The
steep slopes of the continental shelf on the eastern Australian margin
may induce underwater landslides capable of producing localised
tsunamis...
- The Joint
Australian Tsunami Warning Centre - The
establishment of the fully functional Australian Tsunami Warning
System is a four-year project funded by the Federal Government that is
due to be completed in June 2009. At the completion of the project
Australia will have considerably improved earthquake and tsunami
detection equipment in Australia and around the region, enhanced
scientific modelling of tsunami, a responsive warning system, and
increased public awareness and community preparedness.
- EMA: Australian
Tsunami Alert System
- Tsunami
warning system will 'stop false alarms'
- Science of Tsunami Hazards:
TSUNAMI SCENARIO SIMULATOR: A TOOL FOR ENSURING EFFECTIVE DISASTER
MANAGEMENT AND COASTAL EVACUATION IN A MULTILANGUAGE SOCIETY
+ TSUNAMI
PUBLIC AWARENESS AND ITS ROLE IN RISK EDUCATION "The
2004 Indian Ocean tsunami has demonstrated that large magnitude,
destructive tsunami occur in areas close to Australia. The commitment
by the Australian Federal Government to the development and
installation of an Australian Tsunami Warning System is a vital element
in helping to keep Australian coastal communities and public and private infrastructure and assets safe from
tsunami. However, the physical components of the warning system are
only one element of making Australia safe. The other, perhaps
more important element, is preparedness and response. Emergency
Management Australia and the State Emergency
Services are the agencies tasked with the responsibility of evacuating
coastal communities if required. The success or otherwise of public
response to tsunami warnings will be dependent on their understanding
of tsunami hazard and risk. We provide selected results from a pilot
investigation into public awareness of tsunami risk in the Sydney
region – a fundamental necessity for developing appropriate
risk
mitigation strategies. Our questionnaire survey of members of
the
general public and coastal council professional officers indicates that
little has been learned since the December 2004 Indian
Ocean tsunami disaster.
This presentation provides a summary of what the public knows and
importantly, does not know with respect to tsunami. We make a series of
recommendations to assist responsible organisations in thinking about
risk mitigation."
- 28 Aug 08 A survivor
of the Indian Ocean Tsunami started a Facebook page to
raise awareness of the risk (page removed in 2016 - beware of false identities)
- May 08: Taking
a punch: Building a more resilient Australia - report "We need greater clarity
on the precise management and
coordination arrangements in the case, for example, of a devastating
tsunami impacting on southeast Australia...The Commonwealth agency seen
to be responsible for this, Emergency Management Australia (EMA), has
no mandate, legislation or Cabinet endorsement with which to take
command. The delivery of EMA functions for the most part is the result
of goodwill on behalf of other agencies. This is clearly not
a satisfactory situation."
"A $70 million early warning system is being set up to record
any
earthquakes that could trigger giant waves to strike the NSW coast but it’s
not clear how communities get informed, particularly if a
night-time incident occurred..."
- Why
weren't we warned? Fiction to raise awareness
- The
Australian Tsunami Warning System and lessons from the 2 April 2007
Solomon Islands tsunami alert in Australia - Dale
Dominey-Howes, UNSW & others "This
has taught us two important lessons. First, the physical warning system
is not enough in itself to result in a reduction of vulnerability to
tsunami. Just because we have a warning system does not mean the job is
done. Second, much work needs to be undertaken to ensure that
communities have been educated about tsunami hazard and risk and what
alert and warning messages mean, how to react, where to evacuate and
how quickly to respond. Furthermore, the emergency services and the Emergency Management Australia must work
urgently to effect community tsunami disaster management planning,
identification of safe evacuation zones, testing and evaluation of
tsunami warning messages and trialing of these plans with the public."
+ Geological
and historical records of tsunami in Australia (abstract)
+ Tsunami
and palaeotsunami depositional signatures and their potential value in
understanding the late-Holocene tsunami record (abstract "we
are unable to replicate the previously reported findings of tsunami
deposits...") + Tsunami
risk mitigation and the issue of public awareness
- Emergency
management of tsunami in New South Wales and the response to the
Solomon Islands tsunami April 2nd 2007 - Australian Journal
of Emergency Management
Update July 2006 with
advice from EMA (see also Australian
news)
Key points (thanks Mark Sullivan, Director Capability Development EMA):
- EMA is working with States and Territories and relevant
industry,
education, volunteer and community sectors to enhance community
preparedness through awareness raising, education and
training.
- Over
four years, from July 2005 to June 2009, the Bureau of Meteorology,
Geoscience Australia (GA) and Emergency Management Australia (EMA) will
implement a comprehensive end-to-end Australian Tsunami Warning System
(ATWS). The ATWS will be delivered through enhancements to the existing
Australian Tsunami Alert Service (ATAS), and will comprise upgraded
seismic and sea level monitoring networks, computer modelling of
tsunami propagation to aid impact forecasting, and national awareness
raising and capacity building initiatives. The ATWS, once
fully
operational, will deliver timely and accurate warnings to the
Australian community in such a way as to elicit an appropriate response
from those at risk.
- By 2007 estimates will have been made of the credible limit
of offshore tsunami wave height for the entire Australian coastline.
- Inundation modelling is being undertaken for some West
Australian coastal communities
- Australian Emergency Management Committee's Tsunami Working
Group
will meet in September 2006 with a view to agreeing on a
national
strategy for awareness raising and capacity building. Some
local
jurisdictions have already developed hazard specific arrangements for
tsunami, and EMA is committed to working with all jurisdictions to
enhance these already existing arrangements to effectively respond to a
rapid onset event such as tsunami, including the eduction sector.
- Communities and key stakeholders have been, and continue to
be,
engaged; and a national picture of tsunami risk is being developed. In
the very near future, the Australian community can expect to be
provided greater access to relevant
awareness material, and those with key responsibilities will further
benefit from tailored education, training and exercising. On this
basis, the Australian community will come ever closer to being a
'Tsunami Aware Community', and thus be better prepared to respond
appropriately to signs of tsunami in Australia and overseas, as well as
respond in a timely and appropriate way to ATWS warnings.
Related links
- Australian
Journal of Emergency Management:
- Observations
on Tsunami disaster in Papua New Guinea - 1998
- After
the Wave:
A wake up warning for Australian coastal locations King and Gurtner
consider Australia’s vulnerability to tsunamis and storm
surges...The increasing emphasis on disaster reduction through
mitigation
and preparedness has put greater responsibility on local government and
relevant authorities to ensure
that such lessons are understood and used to mitigate future
contingencies. The tsunami is a warning that
reinforces current mitigation efforts, and in particular, the long-term
goals of education and the planning
of coastal land use.
- Tsunami
risk mitigation and the issue of public awareness (PDF) - Is
Sydney at risk from tsunami
flooding and if so, from where? Approximately
330,000 people in New South Wales
live within 1km of the ocean or a coastal river and at an elevation of
no more than +10 metres above sea level (Molino Stewart, 2005). These
people, their homes,
businesses and all infrastructure are vulnerable to the effects of
tsunami inundation...
- Managing
tsunami risk in coastal communities: identifying predictors of
preparedness.
- Early
warning systems: reframing the discussion - The emphasis on
early warning systems has turned attention and funding to the current
capabilities and developments in science and technology, and
unfortunately, distracted us from the central issue of addressing the
real needs of the communities and people at risk.
This horrific tsunami was
caused
by an
earthquake - not an asteroid - but the consequences are
similar.
Like the
asteroid threat,
warnings from
experts about the risk and consequences of major tsunami have been
largely ignored, except in Japan and Western USA.
Japan and the USA have a very a
effective
tsunami
warning system in the Pacific Ocean. It is based, partly, on
pressure
sensors on the ocean floor. Tsunami waves are so long that
they
change
the pressure at the seafloor whereas wind waves get smoothed out.
It would be possible to set up a similar tsunami warning system in the
Indian Ocean - for a few $million (ie the cost of a few cruise
missiles)!
However some locations, such as Sumartra, were probably too close to
the source of the tsunami for a warning system to be effective and in
other areas communication limitations might hinder evacuation.